根系通气组织发育程度对水稻苗期生长及氮素吸收的影响  

Effects of Root Aerenchyma Development Degree on Rice Growth and Nitrogen Absorption at Seedling Stage

作　　者：石承智 王瑞 施卫明[1] 李奕林[1] SHI Chengzhi;WANG Rui;SHI Weiming;LI Yilin(State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]土壤与农业可持续发展国家重点实验室(中国科学院南京土壤研究所),南京210008 [2]中国科学院大学,北京100049

出　　处：《土壤》2023年第3期528-536,共9页Soils

基　　金：国家重点研发计划项目(2022YFD1900702-7)资助。

摘　　要：水稻苗期由于根系通气组织发育不完善导致根际缺氧是限制水稻生长的因素之一。本研究在水培条件下通过施用不同种类通气组织刺激剂(硝普钠、亚硒酸钠、硫氢化钠)研究其对水稻苗期生长、氮素积累、根系内部通气组织发育(孔隙度)及外部形态、根际氧含量的影响。结果表明,不同通气组织刺激剂均能通过刺激通气组织发育改善根际氧环境从而促进苗期水稻生长。其中施用0.01 mmol/L亚硒酸钠处理效果最佳,植株干物质量、氮积累量、根孔隙度及根际氧含量分别较不添加刺激剂的对照处理显著增加36.7%、16.1%、57.3%和39.9%。无论是生物量还是氮积累均与水稻苗期通气组织发育程度存在一个明显的突变阈值(42%),当孔隙度小于该阈值时,孔隙度每增加1%时,单株水稻生物量和氮积累量分别显著增加8.8 mg和0.2 mg;而当孔隙度超过阈值时,二者则迅速降低。因此,苗期添加适宜浓度的通气组织刺激剂可以通过提高根系泌氧来缓解苗期水稻根际环境中溶解氧不足对水稻发育的抑制,同时也为提高水稻氮素吸收提供新的思路。Lack of dissolved oxygen in the rhizosphere environment induced from underdeveloped root aerenchyma of rice at the seedling stage is one of the factors limiting rice growth.Different kinds of aerenchyma stimulants(sodium nitroprusside,sodium selenite and sodium hydrosulfide)were used to determine the biomass,nitrogen accumulation,root aerenchyma development(porosity),root external morphology,and rhizosphere dissolved oxygen at the seedling stage under hydroponic cultivation.The results show that all treatments can enhance rice growth by stimulating the development of root aerenchyma,and improve rhizosphere oxygen content at the seedling stage.Among all stimulants,0.01 mmol/L sodium selenite treatment has the best effect,rice dry matter,nitrogen accumulation,root porosity and rhizosphere oxygen content are significantly increased by 36.7%,16.1%,57.3%and 39.9%compared with control treatment(without stimulant addition),respectively.An obvious threshold(42%)is observed in root porosity no matter with rice growth or nitrogen accumulation at the seedling stage.When root porosity is less than the threshold value,rice dry matter and nitrogen accumulation are significantly increased 8.8 and 0.2 mg per plant for each 1%increase in porosity,respectively.When porosity is more than the threshold,the above indicators are both rapidly decreased.Therefore,a suitable concentration of aerenchyma stimulant can alleviate the inhibition of rice development caused by insufficient dissolved oxygen in the rhizosphere environment at the seedling stage,by increasing the root oxygen loss of roots,which provides a new way for improving rice nitrogen use efficiency.

关 键 词：水稻 通气组织 根系泌氧 氮素吸收 根际环境 

分 类 号：S511[农业科学—作物学] S154.4[生物学—生态学] Q142.9[生物学—普通生物学]